Applied, thanks!
Damien Zammit, le dim. 26 févr. 2023 01:31:18 +0000, a ecrit:
> NB: This relies on a fix for QEMU as one-shot PIT mode
> is currently broken in qemu.
> ---
> i386/i386at/ioapic.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/i386/i386at/ioapic.c b/i386/i386at/ioapic.c
> index 24e04653..d2ea84ad 100644
> --- a/i386/i386at/ioapic.c
> +++ b/i386/i386at/ioapic.c
> @@ -151,8 +151,9 @@ ioapic_toggle_entry(int apic, int pin, int mask)
> }
>
> static uint32_t
> -pit_measure_apic_hz(void)
> +pit_measure_10x_apic_hz(void)
> {
> + volatile int i;
> uint32_t start = 0xffffffff;
>
> /* Prepare accurate delay for 1/hz seconds */
> @@ -162,7 +163,8 @@ pit_measure_apic_hz(void)
> lapic->init_count.r = start;
>
> /* zZz */
> - pit_sleep();
> + for (i = 0; i < 10; i++)
> + pit_sleep();
>
> /* Stop APIC timer */
> lapic->lvt_timer.r |= LAPIC_DISABLE;
> @@ -181,13 +183,13 @@ lapic_enable_timer(void)
> {
> /* Set up counter */
> lapic->init_count.r = calibrated_ticks;
> - lapic->divider_config.r = LAPIC_TIMER_DIVIDE_16;
> + lapic->divider_config.r = LAPIC_TIMER_DIVIDE_2;
>
> /* Set the timer to interrupt periodically on remapped timer GSI */
> lapic->lvt_timer.r = IOAPIC_INT_BASE | LAPIC_TIMER_PERIODIC;
>
> /* Some buggy hardware requires this set again */
> - lapic->divider_config.r = LAPIC_TIMER_DIVIDE_16;
> + lapic->divider_config.r = LAPIC_TIMER_DIVIDE_2;
>
> /* Enable interrupts for the first time */
> printf("LAPIC timer configured on cpu%d\n", cpu_number());
> @@ -336,12 +338,13 @@ ioapic_configure(void)
> lapic_enable();
>
> /* Set one-shot timer */
> - lapic->divider_config.r = LAPIC_TIMER_DIVIDE_16;
> + lapic->divider_config.r = LAPIC_TIMER_DIVIDE_2;
> lapic->lvt_timer.r = IOAPIC_INT_BASE;
>
> - /* Measure number of APIC timer ticks in 1/hz seconds
> - * but calibrate the timer to expire at rate of hz */
> - calibrated_ticks = pit_measure_apic_hz() * hz;
> + /* Measure number of APIC timer ticks in 10x 1/hz seconds
> + * but calibrate the timer to expire at rate of hz
> + * divide by 10 because we waited 10 times longer than we needed */
> + calibrated_ticks = pit_measure_10x_apic_hz() / 10;
>
> /* Set up counter later */
> lapic->lvt_timer.r = LAPIC_DISABLE;
> --
> 2.39.0
>
>
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
